Emons G, Schröder B, Ortmann O, Westphalen S, Schulz K D, Schally A V
Department of Obstetrics and Gynecology, Philipps University, Marburg, Germany.
J Clin Endocrinol Metab. 1993 Dec;77(6):1458-64. doi: 10.1210/jcem.77.6.8263128.
Although specific binding sites for LH-releasing hormone (LHRH) and its analogs have been demonstrated in biopsy samples of human endometrial cancer, their biological significance remains obscure. In this study we evaluated whether binding sites for LHRH are also present in the human endometrial cancer cell lines HEC-1A and Ishikawa and if such sites could mediate antiproliferative effects of LHRH analogs. Using [125I,D-Trp6]LHRH as a ligand, a high affinity/low capacity binding site was detected in both lines: HEC-1A line, dissociation constant (Kd)1 = 5.7 x 10(-9) mol/L, binding capacity (Bmax)1 = 78 fmol/10(6) cells; Ishikawa line, Kd1 = 4.2 x 10(-9) mol/L, Bmax1 = 29 fmol/10(6) cells. In addition, a second class of low affinity/high capacity binding sites for LHRH was demonstrated (HEC-1A line, Kd2 = 1.4 x 10(-6) mol/L, Bmax2 = 21 pmol/10(6) cells; Ishikawa, Kd2 = 4 x 10(-6) mol/L, Bmax2 = 32 pmol/10(6) cells). In the presence of 10(-5) mol/L agonist [D-Trp6]LHRH (triptorelin), the proliferation of HEC-1A and Ishikawa cell lines was significantly reduced to 76 +/- 2% and 88 +/- 4% of controls, respectively, after 24 h and to 64 +/- 2% and 62 +/- 2%, respectively, after 6 days. Dose-response experiments showed that lower concentrations (10(-9) mol/L) of the agonist decreased the proliferation to 80 +/- 1% for the HEC-1A line and 71 +/- 2% of controls for the Ishikawa line after 6 days. Antiproliferative effects are enhanced by increasing the doses of triptorelin and were maximal in this series of experiments at 10(-5) mol/L, the proliferation in the HEC-1A line being 62 +/- 1% and in the Ishikawa line 52 +/- 2% of controls, respectively. Similar time- and dose-dependent antiproliferative effects were obtained in both cell lines with the LHRH antagonist SB-75 (cetrorelix). These data suggest that LHRH analogs can directly inhibit the proliferation of human endometrial cancer cells in vitro. This direct action could be mediated through the high affinity LHRH binding sites.
尽管在人子宫内膜癌活检样本中已证实存在促黄体生成素释放激素（LHRH）及其类似物的特异性结合位点，但其生物学意义仍不清楚。在本研究中，我们评估了LHRH结合位点是否也存在于人子宫内膜癌细胞系HEC-1A和Ishikawa中，以及这些位点是否能介导LHRH类似物的抗增殖作用。使用[125I,D-Trp6]LHRH作为配体，在这两种细胞系中均检测到一个高亲和力/低容量结合位点：HEC-1A细胞系，解离常数（Kd）1 = 5.7×10（-9）mol/L，结合容量（Bmax）1 = 78 fmol/10（6）个细胞；Ishikawa细胞系，Kd1 = 4.2×10（-9）mol/L，Bmax1 = 29 fmol/10（6）个细胞。此外，还证实了LHRH的第二类低亲和力/高容量结合位点（HEC-1A细胞系，Kd2 = 1.4×10（-6）mol/L，Bmax2 = 21 pmol/10（6）个细胞；Ishikawa细胞系，Kd2 = 4×10（-6）mol/L，Bmax2 = 32 pmol/10（6）个细胞）。在存在10（-5）mol/L激动剂[D-Trp6]LHRH（曲普瑞林）的情况下，24小时后HEC-1A和Ishikawa细胞系的增殖分别显著降低至对照的76±2%和88±4%，6天后分别降低至64±2%和62±2%。剂量反应实验表明，较低浓度（10（-9）mol/L）的激动剂在6天后使HEC-1A细胞系的增殖降低至对照的80±1%，Ishikawa细胞系降低至对照的71±2%。通过增加曲普瑞林的剂量可增强抗增殖作用，在本系列实验中，10（-5）mol/L时抗增殖作用最大，HEC-1A细胞系的增殖为对照的62±1%，Ishikawa细胞系为对照的52±2%。使用LHRH拮抗剂SB-75（西曲瑞克）在两种细胞系中均获得了类似的时间和剂量依赖性抗增殖作用。这些数据表明，LHRH类似物在体外可直接抑制人子宫内膜癌细胞的增殖。这种直接作用可能是通过高亲和力LHRH结合位点介导的。
